Lock seam for pipe sections



' April 4, i953 w. J. GRAY LOCK SEAM FOR PIPE SECTIONS Filed Aug.l 21, 1950 Patented Apr. 14, 1953 Locri sEAM Fon PIPE sEc'rIoNs William J. Gray, Rochester, N. Y., assigner to Gray Metal Products, Inc., Rochester, N. Y., a

corporation of New York Appncation August 21, 195o, serial No. 180,596

1 Claim.

The invention relates to a lock seam for ,pipe sections. l

An object of the present invention is to improve the construction of lock seams for pipe sections of stove pipes, conduits of air conditioning units, pipes for hot air furnaces and various other conduits, and to provide a simple 'and comparatively inexpensive l-ock seam of vstrong and durable construction formed from a rectangular blank of sheet material and having opposed longitudinal seam edge portions, one of the longitudinal seam edge portions being provided with a groove opening outwardly and having walls arranged at the entrance to the groove closer or of less distance apart than the thickness of the metal of the other plain longitudinal edge portion, whereby when the latter is introduced into the groove the walls thereof will be spread and will frictionally engage the plain longitudinal edge with suicient force to enable a plurality of pipe sections to be assembled for proper positioning of the assembly without liability of the seam members accidentally opening and prior to locking of the seams after the assembly has been properly adjusted and fitted in the position it is to occupy.

A further object of the invention is to provide a lock seam pipe section of this character having on its seam members coacting interengaging locking means located inwardly of the preliminarily engaged portions so that after the pipe sections of an assembly have been properly positioned the coacting locking devices may be snapped into engagement with each other by pressure applied to the pipe sections at points spaced from the lock seam.

A further object of the invention is to construct and arrange the coacting interlocking devices of the seam members so that upon further relative movement of the seam members toward each other after the preliminary engagement of the same, the resiliency of the walls 'of the plain edge receiving groove will operate j locking means and the seams of shorter sections will be locked inthe same manner and as se- 'curely as th'e'"seams of standard sections.

claim, may be resorted to without departing from the spirit of sacricing any of the advantages of the invention.

In the drawing:

Fig. 1 is a front perspective view of a lock seam pipe section constructed in accordance with this invention, the longitudinal edge portions of the pipe section being spaced apart to illustrate the locking means more clearly;

Fig. 2 is a, rear perspective View of the lock seam, the pipe section being sectioned longitudinally from its upper end to a point near its lower end;

Fig. 3 is a view similar to Fig. 2 showing the lock seam closed and the coacting interlocking means of the seam members in engagement with each other;

Fig. 4 is an enlarged detail vertical sectional view taken substantially on the line 4 4 of lFig. s;

Fig. 5 is an enlarged detail sectional view taken substantially on the line 5 5 of Fig. 2; Fig. 6 is an enlarged detail sectional view taken :on the line 6 6 of Fig. 3;

Fig. 7 is an enlarged detail sectional view taken approximately on the line 6 6 of Fig. 3 with the seam members preliminarily engaged and with the coacting locking devices out of engagemen with each other.

In the accompanying drawing in which is illus- L'trated the preferred embodiment of the inven- 40.

tion, I designates a pipe section constructed of a blank of sheet metal or other suitable material of the desired dimension and gauge, having one of its longitudinal edges outset at 2 and bent upon itself twice, forming an outer wall 3, an

intermediate Wall 4, and an inner wall 5. The outer wall 3 and the intermediate wall 4 are connected by a bead 6 and the intermediate wall 4 and the inner wall 5 are connected by a bead 'I of greater size or amplitude than the bead 6 and located at the inner face of the outset portion 2. By providing the bead l of greater size L or amplitude than the bead 6, the intermediate and inner walls converge and gripping edges are provided at the entrance of the groove.

The intermediate wall 4 and the inner wall 5 g converge toward each other and form an outwardly opening groove 8 and before closing of the seam the space 9 between the inner wall and the intermediate wall at the open end of the longitudinal groove 8 is of a width less than the thickness of the metal of the plain edge portion Ill-of the seam. As the distance between the intermediate wall 4 and the inner wall 5 at the space or entrance 9 is less than the thickness of the metal of the plain edge portion I0, the walls 4 and 5 of the groove will be spread or forced apart when the plain edge portion Il! is forced between said walls4 and 5 and will be frictionally gripped by the same for preliminarily closing the seam prior to engagement of the coacting locking devices, hereinafter described, which lock the seam closed.

The inner wall 5 is provided with an extension I I projecting transversely beyond the groove and curved slightly inwardly and forming a guide for facilitating the introduction of the plain edge portion I into the groove and enabling the plain edge portion to deflect readily the inner Wall of the groove. This preliminary engagement of the seam members prior to locking the same positively in fully closed position, enables a plurality of pipe sections to be assembled and fitted into the position they are to occupy prior to locking the seam members in fully closed position. This greatly facilitates the handling, cutting and positioning of pipe sections to 'provide a pipe assembly for any desired location. The preliminary engagement of the seam members enables the pipe sections to be handled in the customary manner and fitted together and even dropped, without the plain edge portion becoming disengaged or separated from the groove of the other edge portion.

@ne end I2 only of the pipe section is crimped, tapered and slightly reduced in diameter to enable it to be fitted in the conventional manner within the uncrimped end of a similar pipe section to assemble the pipe sections, and the pipe section I is provided adjacent the crimped portion I2 with a cylindrical stiifening or reinforcing bead I3.

While the pipe section may be of any desired length it is designed to be of a standard customary length of approximately 24 inches with 2 inches at one end for the crimping of the pipe section and the formation of the reinforcing bead I3.

The plain edge portion I0 is provided with end and intermediate locking detents I4 formed -by slitting the sheet metal at I5 and indenting and deflecting the sheet metal at the slit to form the detent I4 which has an inclined or beveled front face I6 and an inner or rear shoulder I1. The inner wall 5 of the other seam member is provided inwardly of the extension II with a slot I8 of a size to receive the detent I4 which, when the seam members are completely closed, projects through the slot I8 with its shoulder I1 in engagement with the outer end wall of the 'slot I8. When the detent I4 is engaged with the slot I8, the seam members are securely locked against separation. Y

The inner wall 5 is also provided outwardly beyond the slot I8 with a countersink I9 which is arranged to receive and guide the detent I4 during the preliminary positioning of the seam members. The countersink I9 prevents the detent I4 from offering any resistance to the p-reliminary positioning of the seam members and the detent is arranged in the countersink while the seam members are preliminarily 'engaged with each other prior to complete locking of the seam. After the assembly of the pipe sections and the proper positioning of the same, the detent I4 is forced inwardly beyond the countersink I9 and into engagement with the slot I8. The bottom of the countersink is inclined at its inner portion to enable the detent to ride readily over the intervening portion of the inner wall 5 between the countersink and the slot I8.

The pipe section is provided with end and intermediate locking devices consisting of the detent I4 and the slot I8, as clearly illustrated in Figs. l to 3, inclusive, of the drawing. The end locking devices are designed to be located approximately one-half inch from the ends of the pipe section and the intermediate locking desink, the detent being engaged with the countervices, which are preferably three in number but which may be of any desired number, are designed to be spaced apart 51/2 inches. This location of the locking devices has been found practical and adequate and will enable the pipe section to be cut to provide a shorter pipe section which may be varied in length and which, when cut, will be provided adjacent each end with the coacting locking devices.

The seam member which is provided with the outwardly facing groovemay be formed on the conventional roller machine and the coacting locking means for securing the seam members in their closed position may be die-cut and punchpressed or formed in any other desired manner.

I claim:

A pipe section constructed of sheet material and having opposed longitudinal edge portions, one of the longitudinal edge portions being plain, the other longitudinal edge portion being rearwardly folded upon itself and then folded forwardly upon said first fold, forming an intermediate wall and an inner wall, the intermediate and inner walls forming an outwardly opening groove to receive the other opposed plain edge portion,v the entrance to the groove being of a width less than the thickness of said plain edge portion for preliminarily gripping the same, said inner wall having an extension projecting forwardly beyond the entrance to the groove and arranged to guide the plain edge portion into the groove to effect a preliminary closing of the seam, said inner wall being provided 'rearwardly of the entrance to the groove with a slot and having a countersink located forwardly of and adjacent the entrance to the groove in alignment with said slot, and the plain edge portion being provided on the inner side thereof with a detent that is adapted to be received within the countersink and thereby guided and aligned with said slot in the preliminary engagement of the plain edge portion with the walls of the groove, the detent engaging the slot upon further inward movement of the plain edge portion within the groove.

WILLIAM J. (ZTRAY.

References cited in the me of this patentv UNITED STATES PATENTS Number Name Date i 657,992 Smith Sept. 13, 1900 1,534,990 Pritchard ADI. 21, 1925 1,673,642 Ruppelt June 12, 1928 2,038,389 Siebenlist Apr. 2l, 1936 2,201,409 Sebenllst May 21, 1940 2,214,480 SCheCtel' Sept. 10, 1940 

